Dietary exposures being assessed in human populations include consumption of specific food groups and food items, such as meat, fruits and vegetables, ethnic dishes, and coffee; macronutrient and micronutrient intake, such as fat, vitamin A, carotene, vitamin C, or folacin; general nutritional status; anthropometry; biochemical indices, such as serum cholesterol, serum vitamin A, or serum uric acid; and cooking practices. Cancers being studied include those of the colon, rectum, breast, esophagus, pharynx and oral cavity, lung, cervix, pancreas, stomach, and kidney. Case-control studies have been initiated in high-risk areas with unusually high mortality from cancers conceivably related to diet and among migrants whose changing cancer rates appear related to new lifestyles, such as Japanese-Americans. Selected cohorts with relevant dietary or biochemical data already collected, such as HANES I participants, are being followed-up. Data from HANES I and II and the USDA Food Consumption Survey are being analyzed to test specific hypotheses, such as the relationship of age at menarche to diet, and to provide descriptive information on U.S. dietary patterns, diet variation, and the determinants of nutrient intake.